Wobble pump



A. R. BRAUN WOBBLE PUMP May 26, 1970 Filed May 14, 1968 5 Sheets-Sheet 2 I l/Mar 2. 5/21 INVENTOR.

Irma/vi) WOBBLE PUMP Filed May 14, 1968 3 Sheets-Sheet 5 fig /.5'

Anfi w F. 5/400 INVENTOR.

BY 7 A421 United States Patent 3,514,233 WOBBLE PUMP Arthur R. Braun, 209 E. Mildred, Cary, Ill.

Filed May 14, 1968, Ser. No. 728,954 Int. Cl. F04c 1/02, 5/ 00, 23/00 US. Cl. 418-56 a 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a pump and more particularly to a rotary type of pump which utilizes a flexible integral vane between the piston and the cylinder wall.

A great diversity of uses and applications exist for the employment of hydraulic pumps. To meet such demand, a great variety of pumps have been produced. In all instances a simple efficient operation with little friction is desired. It also should be economically produced. Occasionally corrosion resistance and good seals are needed.

An object of this invention is to provide such a pump with a simplified structure.

Another object is to provide a pump of the above character which can be easily and economically mass produced by plastic injection mold technique.

Still another object is to provide a pump which is inert to corrosive liquids in its entire structure.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

In its most elementary form the pump, of the invention, comprises a substantially cylindrical pump chamber with an eccentrically driven piston, said piston being attached to the inner wall of said chamber by a flexible integral vane with the inlet and outlet ports located on opposite sides of the vane.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

FIGS. 1 through 4 are sequential views of the initial, or priming, stroke with the top wall of the pump chamber removed.

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 1.

FIG. 6 is a cross-sectional view taken along line 6--6 of FIG. 1.

FIG. 7 is an end view of the eccentric cam driver.

FIG. 8 is a vertical view of the cam driver of FIG. 7.

FIGS. 9 through 12 are sequential views of the stroke of a second embodiment with the top wall of the pump chamber removed.

FIG. 13 is an axial cross section of a third embodiment.

FIGS. 14 and 15 are perspective detail views of button cranks of the third embodiment.

Similar reference characters refer to similar parts throughout the several views of the drawings.

Describing first the basic pump unit of this invention, reference should be had to FIGS. 1 through 8. In these views it can be seen that the invention comprises in combination a cylinder block 8 with a chamber 10, a piston Patented May 26, 1970 12, and a flexible integral separator vane 14, integral with the piston and the cylinder block. Inlet port 1 6 and outlet port 18 are disposed on opposite sides of the vane. An eccentric cam driver 20 rotates the piston eccentrically. The chamber 10 is substantially cylindrical and is provided with inlet and outlet passages 22 and 24 leading to inlet and outlet ports 16 and 18, respectively. Bottom wall 37 of the chamber 10 is provided with a hub 26 axially positioned on said wall. The flexible separator vane 14 originates at the far end of passages 22 and 24 near inlet port 16 and terminates at piston 12. It is integral with the piston so that the piston is, in a sense, integral with cylinder 10. Indeed these parts may be molded out of plastic as one piece.

The piston comprises an outer annular piston wall 28, a concentric axial bushing 30, and a radial spacer disk 32 extending therebetween.

As best seen in FIG. 8, eccentric cam drive 20 consists of shaft 34 with a terminal lip 36, and an axially offset, or eccentric, cam 38. Shaft 34- is of a proper diameter to rotate smoothly within hub 26 in wall 37 while cam 38 rotates smoothly within axial bushing 30. During such rotation, the lower surface of lip 36 (as seen in 'FIGS. 5 and 8) rides against the inside surface of bottom wall 37 of chamber '10 and positions the piston with the chamber. Wall 39 covers the top side of the chamber. The terms bottom and top are used in a relative sense, for it should be realized that the pump of the invention may be used in positions other than that shown.

Shaft 34 is provided with an axial recess 42 which may be keyed, threaded, or in some other convenient manner, affixed to a rotary drive shaft of a power source (not shown).

The amount of offset of cam 38 or the difference in diameters between chamber 10 and piston 12 may be varied to suit the desired pumping rate and volume. The diife rence in radii between said chamber 10 and said piston 12 must, however, be equal to the offset of cam 38 so that the outer surface of piston 12 contacts cylinder chamber 10 as it rotates.

In the operation of the pump, an external power source drives shaft 34 in a rotary manner. Cam 38 is thereby caused to rotate about the axis of shaft 34. Meanwhile cam 38 rotates within bushing 30. This causes piston 12 to rotate or wobble within chamber 10, its outer end wall making contact with the outer annular wall of chamber 10. The line of contact between piston 12 and chamber 10 moves progressively around outer annular chamber wall 11 in either a clockwise or counterclockwise fashion depending on the direction of rotation imposed on shaft 34. For the purpose of illustration the invention is shown to operate in the clockwise mode (FIGS. l-4).

In FIG. 1 the line of contact is at a position corresponding to 9 oclock on a clock face. As this line of contact progresses, the portion of chamber 10that is exposed to inlet port 16 increases in volume. Fluid is thereby drawn from port 16 through inlet passage 22 into chamber 10. In FIG. 2 the line of contact has progressed degrees to a position corresponding to 12 oclock with a still greater volume of chamber 10 exposed to port 16. FIG. 3 shows the line of contact at 3 oclock with still more fluid drawn into chamber 10. As the initial stroke is terminated (FIG. 4) the contact surface returns to the original or 6 oclock position. The pump is now fully primed and all subsequent strokes will hereafter be similar to the initial stroke except that fluid will now be present in the portion of chamber 10 exposed to outlet port 18. Since the volume of this portion, exposed to port 18, continuously decreases during the operating stroke, fluid is forced into outlet passage 24. After passage 24 becomes filled, all additional fluid is forced out port 18.

It should be noted that during the stroke of the pump, separator vane 14 flexes so as to allow piston 12 to wobble within chamber 10, yet efiectively isolates passages 22 and 24 from each other.

It will be noted that there is a slight clearance between piston 12 and side walls 37 and 39. It will also be noted that piston 12 actually rolls around the outer annular chamber wall 11 and that vane 14 flexes back and forth and to and fro as the piston is actuated. Hence, the only area of friction is at the hub 26 and at the cam 38. No piston rings are used. In essence, the structure provides a pulsating flow and such is more than acceptable for a great many applications, such as fish aquarium use and the like. Where it is desirable to have a more continuous flow, the second and third embodiments now to be described provide two methods for a smoother flow.

The second embodiment (FIGS. 9 to 12) comprises the use of multiple separator vanes 114 angularly spaced around the piston and chamber. While any reasonable number of such vanes 114 might be employed, for the purpose of illustration, only two are shown in the drawings. Each separator 114 is provided with passages 122 and 124, and ports 116 and 118 as described in the primary embodiment. The angular spacing of separators 114 is preferably equal to 360 degrees divided by the number of separators employed; 180 degrees in the example shown.

FIGS. 9 through 12 show sequentially, one stroke of the second embodiment of the pump. As before these views show the contacting surface at four positions 90 degrees apart and corresponding to 9, 12, 3 and 6 oclock. In this embodiment however, chamber 110 is permanently divided by separator vanes 114 and piston 112, the fluid in the left half of chamber 110 being driven through the outlet 118 at the upper left in the views (FIG. 9) and the fluid in the right half being driven through the outlet 118 at the lower right (FIG. 11). In this manner the pulse of the primary embodiment is separated into multiple smaller pulses. The volume of fluid pumped will be nearly the same in either embodiment, that being the difference in the volumes of chamber 110 and piston 112.

It should be noted that in the second embodiment, inlet port 116 is exposed to outlet port 118 during the course of the stroke (FIGS. 9 and 11). At this point any pressure differential between inlet and outlet pressures could cause a substantial feedback. This may be avoided by simply placing a one way flow valve presently available and well known in the trade, within each port 116 and 118.

Two possible manifold systems 114 and 146 are illus trated in FIGS. 11 and 12 wherein ports 116 are con nected in parallel to a single inlet tube 148 and ports 118 are likewise connected in parallel to a single outlet tube 150.

The third embodiment (FIGS. 13-15) illustrates still another method for providing a more continuous flow. This embodiment can also be employed to provide an increased volume of flow. In this embodiment, multiple pumps of either type described hereinbefore, but preferably of the first embodiment, are interconnected axially in battery.

The first pump is driven by an eccentric cam driver 20 exactly as described earlier. All subsequent pumps are axially drivewise connected by button cranks 52. These button cranks 52 consist of a male driver 54 and a female follower 56.

Driver 54 has an eccentric power arm 58 mounted, axially offset, on stepped seal disk 60. A stud 62, preferably of polygonal shape, such as an octagon protrudes therefrom.

Follower 56 has a stepped seal disk 64 in reverse mating configuration to disk 60 of driver 54. Recess 66 within disk 64 is of matching polygonal cross section to stud 62. An axially offset follower cam 68 extends from disk 64.

With such structure, successive pumps of the first embodiment described above may be aligned in stacked array as seen in FIG. 12. Or, it may be subsequently enlarged by adding units.

The studs 64 may be angularly displaced between successive pumps so that the pulses from the individual pumps may be timed sequentially, in unison, or in any stroke order whereby different pump effects may be attained. The inlet and outlet to each pump unit, although not shown in detail, are obviously so located to enable parallel hookup as in the second embodiment.

It should now be evident that a simple pump with few moving parts has now been devised. There is little contacting surface between the chamber and the piston and since the piston effectively rolls around the outer chamber wall with no sliding friction, a minimum amount of friction losses are incurred. Furthermore, the structure is of such nature as to lend itself to mass production by eflicient injection molding technique and since plastic may be used for all the parts corrosion resistance is easily attained and maintained.

It will thus be seen that the objects set forth above, among those made apparent from the preceding descrip tion, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Now that the invention has been described,

What is claimed is:

1. A pump comprising a cylinder block with a cylindrical chamber therein, a cylindrical piston of smaller diameter in said chamber, at least one flexible separator vane integral with said block and said piston, said block, piston, and separator vane being constructed of the same unitary material eccentric drive means for said piston, and an inlet and an outlet located on opposite sides of said vane whereby upon driving of said piston in said chamber in an eccentric manner liquid is received from said inlet and pumped to said outlet. 1

2. The pump of claim 1 wherein said block, piston and vane are formed of plastic as an integral unit and said inlet, outlet and drive means are affixed thereto subsequently.

3. The pump of claim 1 wherein said drive means comprises an eccentric cam driver consisting of a shaft and an offset cam at one end with seal means spaced therebetween, said shaft fitting within a hub on the body of the cylinder and said cam fitting within an axial bushing on said piston.

4. The pump of claim 3 wherein the difference in diameter of said piston and said chamber is equal to the offset of the cam on said shaft.

5. The pump of claim 1 wherein a plurality of separator vanes are utilized equally spaced about said piston and wherein each vane is spanned by an inlet and an outlet, each inlet and each outlet being interconnected with each other for a smoother less pulsating flow.

6. The pump of claim 5 wherein said interconnection mvolves common inlet and outlet manifolds.

7. A battery of pumps wherein multiple pumps of the type of claim 1 are interconnected axially through button cranks, each of which comprises a male driver with an offset power shaft and a female follower with an offset follower cam extending therefrom, said male driver being pivotally connected to one piston of adjacent pumps and said female follower being pivotally connected to the other piston of said adjacent pumps whereby driving of one pump will drive said second pump.

8. The battery of pumps of claim 7 wherein the inlet and outlet of each pump communicate with a common manifold for each.

9. The battery of pumps of claim 7 wherein said button cranks are offset in a manner to effect sequential pump action to minimize pulse effect.

(References on following page) References Cited 6 FOREIGN PATENTS UNITED STATES PATENTS 500,083 2/ 1954 Canada.

7/1945 Van Ranst 103132 12/1950 Knuth 103 131 WILLIAM L. FREEH, Pnmary Examlner 8/1962 Ketterer 103-132 5 W. J. GOODLIN, Assistant Examiner 10/ 1966 T akebayashi 74597 

